Sub-Saharan African urbanisation and global environmental change

Scientific evidence for global environmental change in Africa presents a prima facia case for increased human migration and displacement. Closer scrutiny of the evidence on demographic change, however, suggests that migration and displacement are less important variables in explaining the human dimensions of global environmental change on the continent than is commonly projected. Natural population growth in cities is a more important dynamic in the evolving system of human settlement in Africa and this significant shift in where people live, both now and in the future is overlooked by the emphasis on the potential impact of environmentally induced migration. Even without any movement from the countryside, cities represent the fastest growing sector of the sub-Saharan African population. The existing vulnerability of African cities, with their fast growing populations and weak management means any environmental change is likely to have significant consequences for cities. Taking the sub-Saharan African demographic evidence seriously means that the scholarly and policy emphasis currently directed to GEC migration and displacement might be more effectively redirected to questions of the interface between global environmental change and urban areas.     

Disruption,not displacement: Environmental variability and temporary migration in Bangladesh

Mass migration is one of the most concerning potential outcomes of global climate change. Recent research into environmentally induced migration suggests that relationship is much more complicated than originally posited by the ‘environmental refugee’ hypothesis. Climate change is likely to increase migration in some cases and reduce it in others, and these movements will more often be temporary and short term than permanent and long term. However, few large-sample studies have examined the evolution of temporary migration under changing environmental conditions. To address this gap, we measure the extent to which temperature, precipitation, and flooding can predict temporary migration in Matlab, Bangladesh. Our analysis incorporates high-frequency demographic surveillance data, a discrete time event history approach, and a range of sociodemographic and contextual controls. This approach reveals that temporary migration declines immediately after flooding but quickly returns to normal. In contrast, high temperatures have sustained positive effects on temporary migration that persist over one to two year periods, while migrations decrease during extended periods of extreme precipitation. Building on previous studies of long-term migration, these results challenge the common assumption that flooding, precipitation extremes, and high temperatures will consistently increase temporary migration. Instead, our results are consistent with a livelihoods interpretation in which long-standing household livelihood strategies (both temporary migration and agriculture) are disrupted by environmental variability.     

Using Bayesian belief networks to analyse social-ecological conditions for migration in the Sahel

In order to understand the impact of climatic and environmental changes as well as socio-economic drivers on human migration, it remains a challenging task to find a method to analyse the knowledge from different scientific disciplines in an integrated way.The Sahel region with its high ecological dynamic has a long history of migratory movements. Within this work, we integrate and analyse socio- and natural-scientific data from two Sahelian study areas in Mali and Senegal using Bayesian belief networks. The core of the network’s structure is formed by four main motives to migrate which are education, family, visit and curiosity and sustenance and employment. It is assumed that these motives determine the spatial and temporal patterns of migration. On the basis of submodels for each migration motive, we identify the decisive factors that constitute the socio-economic and ecological conditions with a combination of sensitivity analyses and train-and-test validation method. In combining these factors, the model avoids implying monocausal dependencies and allows an analytical view on the likely consequences of different settings of social-ecological conditions on migration. Furthermore, we use the model to estimate the consequences of alternative future developments in contrasting scenarios.The results show that changing environmental conditions lead to changing patterns of migration, regarding its duration and destination. These patterns can be very specific for different motives and their underlying factors. One principal result of the analysis is that uncertainty in the main income sources correlates with an increase of short-term migrations in order to increase the households' possibilities for income generation. Nevertheless, socio-economic conditions show a greater impact on the people's decision to migrate than environmental conditions.     

Migrant destinations in an era of environmental change

Which destinations will be most impacted by environmental migration? Most research on environmental migration examines the drivers of mobility, identifying the locations that are most affected by environmental change. By contrast, little attention is paid to where migrants might move to in response to these changes. The paper argues that much can be learned from applying established knowledge from the migration research literature to the specifics of environmental mobility. Migration destinations of environmental movers are examined in two different contexts. First, research is reported relating to the migration destinations of populations affected by drought and food insecurity. Second, Europe is studied as a destination region for migration flows. The paper concludes that, in place of estimates of the number of environmental migrants, a more productive focus of research would be to achieve deeper understanding of the destinations selected by current environmental migrants, and to appreciate why immobility is as great a problem as movement to new locations for those concerned with climate adaptation planning.     

Might climate change the “healthy migrant” effect?

Migrants from Mexico to the U.S. tend to be healthier than non-migrants in their origin – part of a pattern termed the “healthy migrant effect”. With climate change altering livelihoods across the globe, we ask how the migration-health connection may be altered by environmental strain. On the one hand, positive health selectivity may be intensified if migration becomes more challenging – and therefore increasingly likely to be undertaken by only the healthiest. On the other hand, positive health selectivity may decline if the “push” associated with environmental strain acts upon individuals regardless of health. We use Mexican Migration Project data to model Mexico-US migration by male household heads with consideration of migrant health as well as recent rainfall conditions in communities of origin. Results reveal intriguing interactions such that when moderately dry regions experience rainfall shortage, health selectivity is lower – meaning that less healthy household heads also engage in international migration. We posit that social networks may underlie this association. We further argue that since environmental context may alter the relationship between migration and health, future research on the “healthy migrant effect” should consider environmental conditions. As to implications, if climate change yields pressure on less healthy individuals to migrate, the need for migrant-sensitive health systems and services may be intensified in destination regions.     

Dealing with displacement: Can “social protection” facilitate long-term adaptation to climate change?

This article explores the possibilities of using social protection to manage and reduce the risks of forced displacement resulting from climate change. It reviews the relevant literature on migration, disasters and climate change, and constructs a model through which international policies may be used to encourage resettlement options that support the capabilities and entitlements of poor and vulnerable populations. By distinguishing between rapid-onset disasters and long-term environmental change, it explores the ways in which cash transfers, asset transfers and conditional cash transfers may be used to break the cycle of vulnerability, destitution and distress migration that can occur during times of severe environmental stress. An important distinction is made between “economic migration,” which implies that households have at their disposal an opportunity to engage in forward-looking analysis about the ways in which they will invest household resources and “distress migration,” which implies that household decisions about investment and migration are largely ad hoc responses to external environmental processes and events. The article reviews recent discussions about the prospects of revising the international refugee regime, and identifies the opportunities and challenges of using social protection to support household decisions that can facilitate economic migration over the long-term.     

The effect of environmental change on human migration

The influence of the environment and environmental change is largely unrepresented in standard theories of migration, whilst recent debates on climate change and migration focus almost entirely on displacement and perceive migration to be a problem. Drawing on an increasing evidence base that has assessed elements of the influence of the environment on migration, this paper presents a new framework for understanding the effect of environmental change on migration. The framework identifies five families of drivers which affect migration decisions: economic, political, social, demographic and environmental drivers. The environment drives migration through mechanisms characterised as the availability and reliability of ecosystem services and exposure to hazard. Individual migration decisions and flows are affected by these drivers operating in combination, and the effect of the environment is therefore highly dependent on economic, political, social and demographic context. Environmental change has the potential to affect directly the hazardousness of place. Environmental change also affects migration indirectly, in particular through economic drivers, by changing livelihoods for example, and political drivers, through affecting conflicts over resources, for example. The proposed framework, applicable to both international and internal migration, emphasises the role of human agency in migration decisions, in particular the linked role of family and household characteristics on the one hand, and barriers and facilitators to movement on the other in translating drivers into actions. The framework can be used to guide new research, assist with the evaluation of policy options, and provide a context for the development of scenarios representing a range of plausible migration futures.     

Agent-based model simulations of future changes in migration flows for Burkina Faso

Attempts to quantify the numbers of migrants generated by changes in climate have commonly been calculated by projecting physical climate changes on an exposed population. These studies generally make simplistic assumptions about the response of an individual to variations in climate. However, empirical evidence of environmentally induced migration does not support such a structural approach and recognises that migration decisions are usually both multi-causal and shaped through individual agency. As such, agent-based modelling offers a robust method to simulate the autonomous decision making process relating to environmental migration. The Theory of Planned Behaviour provides a basis that can be used to effectively break down the reasoning process relating to the development of a behavioural intention. By developing an agent-based model of environmental migration for Burkina Faso from the basis of a combination of such theoretical developments and data analysis we further investigate the role of the environment in the decision to migrate using scenarios of future demographic, economic, social, political, and climate change in a dryland context. We find that in terms of climate change, it can be seen that that change to a drier environment produces the largest total and international migration fluxes when combined with changes to inclusive and connected social and political governance. While the lowest international migration flows are produced under a wetter climate with exclusive and diverse governance scenarios. In summary this paper illustrates how agent-based models incorporating the Theory of Planned Behaviour can be used to project evidence based future changes in migration in response to future demographic, economic social and climate change.     

Assessment of community preference rankings of potential environmental effects of climate change using the method of paired comparisons

The preference rankings of a rural population in central British Columbia, Canada of potential environmental effects of climate change were assessed using the psychometric method of paired comparison. The survey results were used to develop an interval scale for eight hypothetical, but potential, environmental effects including major and minor impacts to water and fish, forest ecosystems, wildlife, and scenic and recreation. Interval scales were developed for the total sample as well as sub-samples made up of females, males, town residents, non-town residents, respondents with high school or less education, and respondents with at least some post-secondary education. Major impacts on water and fish were considered to be the most serious effects followed by major impacts on forest ecosystems and major impacts on wildlife. Major effects on scenic and recreation were ranked below minor effects on water and fish. Responses from the sub-samples were similar with some minor deviations. For example, females ranked major impacts on wildlife higher than males, and males ranked major impact on scenic and recreation higher than females. However, the overall rankings of females and males were highly correlated. This study showed climate change effects on environmental goods and services in terms of human preferences. A human preferences perspective (combined with biophysical assessments) is required for determining local adaptation priorities and for guiding impacts and adaptation research. The methodology and approach has potential for broader application.     

Global environmental change and migration: Governance challenges

Claims have been made that global environmental change could drive anywhere from 50 to almost 700 million people to migrate by 2050. These claims belie the complexity of the multi-causal relationship between coupled social–ecological systems and human mobility, yet they have fueled the debate about “environmentally induced migration”. Empirical evidence, notably from a 23 case study scoping study supported by the European Commission, confirms that currently environmental factors are one of many variables driving migration. Fieldwork reveals a multifaceted landscape of patterns and contexts for migration linked to rapid- and slow-onset environmental change today. Migration and displacement are part of a spectrum of possible responses to environmental change. Some forms of environmentally induced migration may be adaptive, while other forms of forced migration and displacement may indicate a failure of the social–ecological system to adapt. This diversity of migration potentials linked to environmental change presents challenges to institutions and policies not designed to cope with the impacts of complex causality, surprises and uncertainty about social–ecological thresholds, and the possibility of environmental and migration patterns recombining into a new patterns. The paper highlights fieldwork on rapid- and slow-onset environmentally induced migration in Mozambique, Vietnam, and Egypt. Current governance frameworks for human mobility are partially equipped to manage new forms of human mobility, but that new complementary modes of governance will be necessary. The paper concludes with challenges for governance of environmentally induced migration under increasing complexity, as well as opportunities to enhance resilience of both migrants and those who remain behind.     

Factors affecting whether environmental migration is temporary or permanent: Evidence from Bangladesh

This study examines whether environmental migrants in Bangladesh move permanently or temporarily. The analyses are based on data collected in 2010 and 2011, and cover four themes, namely migrant characteristics, environmental change related factors, conflict and adaptation strategies, and social networks. The estimates obtained from binary logit models show that most sets of variables have statistically significant impacts on the temporary migration versus permanent migration decision. Females are more inclined to migrate temporarily, a finding which is consistent with prior studies that argued that female migration is one temporary household survival strategy in the face of an environmental crisis. The probability of intending to move temporarily is significantly affected by the prior occupational experience: Migrants who were previously engaged in agriculture or fishing are more inclined to migrate permanently. Those households who reported that they had lost assets due to environmental hazards are shown to have a higher probability of becoming permanent migrants. In contrast, loss of livestock and crop failure are associated with a greater likelihood of temporary migration. The empirical results reveal the groups that can be targeted in destination regions in settlement policy, and equally the groups whose return home can be facilitated once any immediate danger has passed.     

Assessing the impact of climate change on visitor behaviour and habitat use at the coast: A UK case study

Although tourism and recreation can bring economic benefits to an area, the presence of visitors may adversely impact biodiversity, particularly if they make use of sensitive environments. It is anticipated that the effects of global climate change alone may increase the vulnerability of many environments, but these effects may be magnified if warmer and drier weather encourages more visitors, or makes them more likely to participate in ecologically damaging activities. Using case study sites from the UK, this study examines how different types of beach visitors make use of coastal environments. Via a series of visitor surveys, information is elicited on the environmental preferences of a range of visitor types including walkers, bird watchers, and bathers. The use of different habitats by these visitors is also assessed via an analysis of walking routes undertaken in a Geographical Information System. From this, an assessment is made of the likely present day biodiversity impacts arising from different coastal users, and how these may change under a modified climate. This study finds that whilst higher temperatures are expected to increase visitor numbers, warmer weather may encourage greater participation in low impact activities such as bathing. The findings are discussed in the context of coastal management.     

Implications of Global Climate Change for Tourism and Recreation in Wetland Areas

Tourism and recreation are important economic activities which are major agents of change globally and, more specifically, in wetland areas. There is a regular round of activities associated with the seasons and anything which influences operating seasons is likely to have substantial consequences for tourism businesses Atmospheric conditions influence both whether or not people will participate as well as the quality of the experience. In marine coasts, wetland recreations may be threatened by rising sea levels but recreation in inland water bodies may be affected more by deficiencies rather than superabundance of water. Marinas and recreational boating are harmed by extremes of both high and low water, particularly the latter which is the most likely situation under global climate change. Two main groups can be considered with respect to the potential to adapt to climate change. These are the participants themselves and the businesses which cater to them. It is argued that the former are likely to be much more adaptable than the latter.     

The search for safety: The effects of conflict,poverty and ecological influences on migration in the developing world

This article discusses how conflict patterns affect the volume, direction and types of migration within the developing world. Conflict impact and poverty are the two primary drivers directly shaping migrations within poor and high-risk environments. Indirect drivers of migration include livelihood fragility, ecological and political instabilities. Conflicts overwhelmingly occur in states where much of the population is dependent upon the environment/natural resources for their livelihoods. There is little reliable evidence to suggest a link between civil conflict and climate change, however, the environmental changes occurring across developing states shape the ways in which civilians can respond to political and economic threats. The crucial point is that the communities who are subject to increasing environmental variation and disruption, through either external or internal processes, are likely to become poorer as a consequence. This poverty lessens their ability to respond to the myriad of threats in their environs, including conflict, ecological disasters, disease, or economic hardship. Hence, there is an endogeneity to conflict, precipitating factors and possible outcomes: the persistence of violence plays a determining role in the sustainability of livelihoods, poverty levels and the propensity of migration within chronically conflicted areas. Those most vulnerable to forced migration live in ‘chronically vulnerable areas’, which are characterized by the deterioration, loss or destruction of primary livelihood systems and productive assets, environmental degradation and deterioration of natural resources, increasing impoverishment of communities and households, geographical isolation and a dependence on relief.     

Carbon reduction in the real world: how the UK will surpass its Kyoto obligations

Carbon dioxide emissions from UK energy use have fallen by more than 20% over the last 30 years, and carbon intensity — carbon emissions per unit of GDP — has halved. These reductions have been achieved by a combination of decarbonisation of the energy system and substantial improvements in energy efficiency. Use of natural gas in power generation has been a big factor in recent years, but energy efficiency improvements in households and particularly industry have been more important over a longer period. Government policies designed primarily to address climate change have not been important contributors, until recently.Future reductions in emissions will require more proactive policies. However, they are possible without any economic difficulties, notably by adopting cost-effective energy efficiency measures, using new renewable energy sources and reducing dependence on private cars. These policies will improve economic efficiency. The new UK Climate Change Programme includes policies that combine regulation, investment, fiscal measures and other economic instruments. By working with the grain of other social, environmental and economic policies, they can achieve far more than a carbon tax alone, set at any politically acceptable level. Modelling the costs of emission reductions using a carbon tax as the only instrument would not only massively over-estimate costs, it would bear little resemblance to real world politics.The paper demonstrates that a more diverse set of policy instruments is likely to be an effective and politically acceptable approach in a mature industrial economy. It is concluded that the UK’s Kyoto target of a 12.5% reduction in greenhouse gas emissions is not challenging. The UK Government’s target of reducing carbon dioxide emissions by 20% between 1990 and 2010 is also achievable. By 2010 per capita emissions from the UK will be well below 2.5 tC per year. Claims that some countries, notably the USA, could not reduce per capita emissions below 6 tC per year seem inconsistent with this experience.     

Human mobility intentions in response to heat in urban South East Asia

Climate change and associated weather extremes and natural hazards have large impacts on the urban population of the Global South where population growth will rapidly increase the already large number of people who will be affected. Using Protection Motivation Theory (PMT), we investigate how hot temperatures, manifested as heat stress, is affecting the intentions of moving among the urban population in three Asian countries (Indonesia, Malaysia, Philippines). We conducted an online survey with 2219 respondents. Almost all respondents (98%) had experienced heat stress, albeit at different levels. When asked whether respondents would be likely to move away from their current locations because of heat, nearly a quarter (23%) reported that they were very likely to do so, and 50% that they probably would. Stronger moving intentions because of heat were associated with women and older people. Concerns about increases from damage from heat (threat appraisal) were more strongly associated with moving intentions than an understanding of the costs and benefits (coping appraisal). Among the threat appraisal, heat stress levels and risk perception were the strongest predictors of moving intentions because of heat. The results contrast with the findings of migration studies in response to sudden onset hazards and underpin the differences in adaptation behaviour in response to different climate change impacts. Moving away to cooler places as an adaptation strategy to heat may be challenging to foresee in terms of timing, capabilities, destination and potential costs because it may not happen soon. We strongly recommend further research on climate change migration of the urban population, including within urban and urban-to-urban movements. While many people move back after sudden onset disasters, heat potentially leads to permanent movements given it is likely to be better planned, and as the habitability of some places is increasingly compromised. Overall the effects of slow onset environmental hazards such as pollution and heat on migration warrant more research attention given the rapidity of urban population growth, particularly in the global south.     

Regeneration in Gap Models: Priority Issues for Studying Forest Responses to Climate Change

Recruitment algorithms in forest gap models are examined withparticular regard to their suitability for simulating forestecosystem responses to a changing climate. The traditional formulation of recruitment is found limiting in three areas. First, the aggregation of different regeneration stages (seedproduction, dispersal, storage, germination and seedling establishment) is likely to result in less accurate predictionsof responses as compared to treating each stage separately. Second, the related assumptions that seeds of all species are uniformly available and that environmental conditions arehomogeneous, are likely to cause overestimates of future speciesdiversity and forest migration rates. Third, interactions between herbivores (ungulates and insect pests) and forest vegetation are a big unknown with potentially serious impactsin many regions. Possible strategies for developing better gapmodel representations for the climate-sensitive aspects of eachof these key areas are discussed. A working example of a relatively new model that addresses some of these limitations is also presented for each case. We conclude that better modelsof regeneration processes are desirable for predicting effectsof climate change, but that it is presently impossible to determine what improvements can be expected without carrying outrigorous tests for each new formulation.     

Economic drivers of migration and climate change in LDCs

Environmental migration is a topic which has given rise to widespread debate and gloomy predictions about the state of the world in 2050, but where rigorous research and empirical evidence are unfortunately in short supply. In this paper, we review the existing research on and empirical evidence of how climate change and climate variability in Less Developed Countries (LDCs) affects two main drivers of migration identified by migration models in the economic literature, namely income level differentials between origin and destination areas and income variability in origin areas, and how they in turn affect migration. We find that there are serious gaps in both the economic and the environmental literature that render it impossible to make sound and robust predictions of how climate change and increased climate variability will affect the economic migration drivers, and of how these in turn may change existing migration patterns. There are some empirical indications that income differentials may increase due to lower income levels in the origin areas of LDCs, but virtually no evidence exists of the effects of climate change or increased climate variability on income variability. Furthermore, although a negative relationship between migration and rainfall has been established by many researchers, there is only very limited evidence as to what drives it. A clearer picture of the driving force behind the link between rainfall and migration would greatly benefit policymaking in this area.     

‘Signals’ from pre-crisis discourse: Lessons from UK flooding for global environmental policy change?

This paper evaluates policy accelerations after past flood crises in the UK (in 1947, 1953, 1998 and 2000) and explores their value as surrogates or metaphors for how governments might respond with policy changes to the local expressions of global climate and environmental change in the future. We find that these past policy change accelerations were, in general, not based on the development of new ideas but on bringing forward existing ideas that were already the subject of widespread professional or public discourse. We suggest, therefore, that we may be able to detect now, as ‘signals’ within current policy discourse, the embryos of the policy shifts that are likely to come about as part of any crisis-response adaptation to future climate change. If this is the case, then we believe that those with policy responsibilities now may be able to begin carefully and proactively to prepare the ground for such policy changes ahead of the crisis events that will alone trigger their acceleration and adoption.     

A first approach to assessing future climate states in the UK over very long timescales: Input to studies of the integrity of radioactive waste repositories

Projected timescales for the transport of radionuclides from an undisturbed undergound nuclear waste repository to the surface are in the range of tens of thousands to millions of years. Over these timescales major natural and potentially major anthropogenic changes in climate can be expected. As part of the UK disposal safety assessment programme, time-dependent models of the repository environment are being developed. The Climatic Research Unit has undertaken a study of relevant climatic change and climatic effects. This has required assessment of the probable range, succession and duration of major climate states likely to be experienced in the UK over very long timescales, up to 10⁶ yr. Two methodologies have been employed. The first uses the Milankovitch theory, which is considered to be the major cause of the Pleistocene glacial/interglacial cycles. The second involves empirical analysis of the long-term reconstructed climate record: no assumptions about the specific causes or mechanisms are made. A period of sub-tropical climate is included in the sequence to represent a period of anthropogenically-induced greenhouse warming. The climate sequence established using these methods will form the basis for studying related processes, such as erosion and groundwater movement and transfer by vegetation, and their implications for radioactive waste disposal. This has involved the construction of instrumental climate analogues.